Device for producing extruded sheet metal



' A. F ROCKWELL.. DEVCE FOR PR'ODUCING EXTRUDEUSHEET METAL.

APPLICATION HLEDJUNE25,1919.

1,423,351- Patented my M1922.

f f f l /f f 1 FIG. 5

INVEN'R.

UNITED f* STATES PATENT OFFICE.

ALBERT F. ROCKWELL, 0F BRISTOL, CONNECTICUT, ASSIGNOR TO MARLIN-ROCKIVELL CORPORATION7 OF NEVI YORK, N. Y., A CORPORATION OF NEW YORK.

DEVIGE FOR PRODUCING EXTRUDED SHEET METAL.

Application filed .Tune 25,

To all whom 'it may; concern.'

Be it known that l', illnanirr RooiiwnnL, a citizen ot the United States, and a resident oil' Bristol, in the county ot Hartford and State of Connecticut, have invented certain nonr and useiiul Improvements in Devices for Producing Extruded Sheet Metal, ot which the following is a specification.

This invention relates generally to apparatus for reducing metal ingots to sheet form.

It has heretofore beenthc'usual land com,- mon practice to produce sheet metal from the original ingots by anumerous an dvaried series oit rolling operations which have made the cost Vot production of the sheet metal linally obtained very high. Not only has the cost been excessive but ior many purposes the quality of the sheet metal produced by rolling processes has not been up to the rigorousstandard desired. I have discovered that I can dispense with several steps in the ordinary process oit reducing the ingot to sheet torni, thus reducing quite materially the cest of production, and in addition produce a sheet metal having greatly improved characteristics with relation tothe quality o'fi the metal in the inal product. I succeed in reducing the ineot in a single operation to a sheet having thickness such that a minimum amount rolling Will sutlire to reduce the metal to a sheet having any desired thinness, and accomplish this by making use of an extrudingf; or squirting process in which a billet oi" the t esired metal is heated to a suitably plastic condition and iforced under pressure to flow through a die which gives the emerging metal the desired conformation.

In the art o'li producing extruded metal, great di'liculty is found in obtaining prodn uct in sheet ilorm because ot the impossibility ot 'forcing plastic metal through an elon gated slit *with an even pressure throughout that will produce a sheet having` uniform ant regular strength and homogeneity of texture. This is the case largely because ot` the different relation that must necessarily exist between the intermediate portions and end portions of the slit and the Wall of the pressure chamber. In addition, the elongated form of die opening requires a pressure chamber Whose size is substantially greater, with a consequent need of enormous pressure, than the minimum size possible to Specification of Letters Patent.

Patented July 18, 1922.

1919. Serial N0. 30G,546.

be achieved when the die opening is circular' in shape as used, i'orv instance, in the production oi' seamless tubing by an oxtruding proce. s with a relatively smaller expenditure olf power. Furthermore, the known success that is had in the production ot' seamless 'tubing by such processes, with the attendant advantages or enhanced and uniform quality and strength in the extruded metal, results in a product having characteristics that malte a satisfactory standard to be striven for in the production oit extruded metal in sheet form. I have discovered that by com'- bining certain steps in the operation of eX- truding metal in tubular form, with novel meansi'for cleaving the tube as it issues from the die and spreading it out into tlat sheet torni, I am able to produceextruded sheet metal having all the advantages in quality and strength of extruded seamless tubing. In order to obtain the ultimate product in the torni of a sheet rather than a tube, I provide means acting coincidently with the eX- truding operation for slitting the tubular wall of inetal as it passes through the die( 'ihe slitting means consists of Ian ou t\vardly extending scoring projection formed along the length olf the outer surface oit the mandrelor inner die member. In order to insure the cleavage of the emerging tube along the scored lino, I` preterably torni the outermost end oit the mandrel `with an enlarged and preferably outwardly-expanded spreader member `which operates to expand the tube as it is pushed outwardly over the spreader vmember occupying theposition ot a core,

and causes the scored tube to split along the scored line so as to present separated edges that can be readily vengaged by suitable iliorining devices provided to open out the split tube and bring it to a flattened sheet term.

In the drawings- Fig. l is a longitudinal vertical section or' an extruding device embodying the'invention and showing the apparatus in condition to begin an operation;

Fig. 2 is a View similar to Fig. l, showing the apparatus in the midst of an operation;

` Fig. 3 is still another view similar to Fig. l. showing the condition of the appara-tus at the completion of an operation;

Fig. 4 is a transverse vertical section taken along the line 5--5 of Fig. l; -1

Fig. 5 is a transverse vertical section of the split-tube-snaped body formed by the apparatus; and

Fig. (l is a view in perspective ot means used for s in'eading` the split tube into l-attened sheet form.

In the drawings, l show a: cylinder l in which a piston 2 is actuated by hydraulic or other suitable pressure to torre a billet of metal 3 throuo'h a die t held in )osition at one end of the cylinder by means ot a cap 5. The metal billets 3 are preferably formed totit the interior oil' the cylinder l and are provided with longitudinally-arranged centraliopenings through which a suitable mandrel ti, arranged to be detachably seated at one end in the piston 2, can be placed. The diameter oi the mandrel 6 is somewhat less than that ot the opening in the die 4: so that an annular die opening 7 is provided 'which imparts to the metal extruded therethrough a tubular or annular formation.`

However, as it is an object oi this, invention to produce extruded metal in sheet rather than in tubular form, I provide means ior scoring the body of metal. as it passes through the annular die opening;r and i also means for expanding"- the scored' tube to the cause it to break along` the scored line and thus provide a longitud'inally-splittube, .and further means for spreadin and flattening out the split tube into suitable sheet torm for beingr passed between compressingr rollers Lfor reduction to' a sheet ont the desired gauge.` Y

, The scoring meansre'ferred to consists of a longitudinally-arranged scoring` edge or rib Which extends substantially along` the' entire lengthV of the mandrel@ in position to indent or score the inner surta-ce ot the tube. shaped member passing through `the die opening. For the vreason that it is not desirable to have the scoring rib 9 on the mandrel maire Contact with the inner surface of the die member t, I do not provide for the complete severance ot' the Wall of the tube by the scoring means,` but preferably arrange that the scoring` rib shall be spaced slightly 'trom the die member. By this arrangement, l provide lor the retentiony ot a thin connecting' strip ol metal along the cored line which can be readily riiptured by ,tion of the tube-expanding member already referred to. This expanding member preferably 'takes the term ol an inwardlyconverging n'iember 'l0' which is permanently secured to the outer end-oit the mandrel 6 an'd'wl'iose greatest diameter is suiliciently greaterfthan that of the'interior of the tube l1 issuing' Vfrom the die to split it along the scored line in the manner indicated in 5V and 'form a substantial gap l2 which facilitates the opening out or spreading of the split tube into dat sheet form.

In the operation .of the device `a hollow cylindrical billet 3 of the desired metal heated to a suitably plastic condition, which would ordinarily be indicated by a red heat,

andtormed to fit the interior of the cylinder 2, is placedl in. the cylinder, the mandrelv 6 is fitted to the head 13 of the piston 2 and passedthrough the hollow billet and the die opening, as indicated in Fig. l of the drawings. The enlarged rear end 14 of the mandrel has a rectangular or equivalent crosssection to prevent rotation oi the mandrel about its axis at the beginning of the scoring operation of the scoringq edge. The establishment olf the alinement ofthe scored linev Y at the beginning of the operation is suiiicient and the aluement tlnisestablished Willi ber maintained throughout the operation because ot the guiding` action that takes place between the elongated scoring), edge 9 and the groove which it 'forms in the face of the I wall ot the tube.

Pressure being applied to the piston 2 a' flowing of the metal composing the billet is caused to take place through the annular opening provided for the purpose between the mandrel' 6 and the diemember 4; The

movement of the metal through the die opening 'in contact with they mandrel causes forward 4movement ot the mandrel also, but at a proportionatelymuch slower rate because of the retarding action iol the'relatively large base member 14 oi the mandrel as compared with the size of the central opening; in theV billet. The result is that while the base member of the mandrel is slowly moving through the resistingl mass of the billetthe tubular extruded member is moving at a comparatively rapid rate over` the enlarged sjn'eadinp; member l() which acts to expand the tube ll'an-d cause the yvall thereof to part along the line :freshly scored by the edge 91 l f i. j

"By mea-ns of the -forming' rollers l5 illustrated in Fig. G of tlie`drawings7 the split tube llis spread and flattened out to the sheet form indicated bythe Hat strip 16. The strip 1G :is in a satisfafi'tory condition for passingbetween suitable rollers for rei duction to the desired thickness.

It will thus be seen that l have succeeded in producing by an extruding process a metal blank having;r a suitable format-ion for Vsubsequent rolling; to its fina-l sheet form.

the corresponding oppositely-disposed portions of the cylinder Walls, whereby a uniformity of flow and pressure through all portions of the opening is secured.

llVhat l claim is:

l. ln a metal Werking device, a die member having an opening through which the metal may be forced in a tubular formation, and means for cleaving the Wall of the tube as it passes through said opening.

2. A device for reducing metal to sheet form comprising: a die member having a die opening of annular formation, means for forcing the metal to be reduced through said die opening, and means for (leaving the metal to produce a blank having the formation of a lungitudinally-split tube.

S3. il device for reducing metal to sheet fornicomprisingl a die member having a die opening of annular formation, means fory forcing the metal to be reduced through said opening', means in said opening for cleaving` the metal as it passes tl'ierethrough to produce a blanl: havin the formation of a longitudinally-split tube, and means for causing the split tube o take the formation el. a substantially flat sheet.

4f. A device for reducing metal to sheet form coi larising: a die member having a die opening of annular formation, means for forcing the metal to be reduced through said annular opening, .means for scoring the metal as it passes through said open* ing, means for e.\;pandin g` the tubular body of metal and causing it to part along` the scored line produced by said scoring means to thereby produce a longitiulinally-split tube, and means for :flattening out the split tube into sheet form.

5. la device for reducing' metal to sheet form comprisino: a die member having an opening. means for forcing the metal to be reduced through said die opening, a inandrel arranged to occupy a position in said die opening to form an annular passage through which lthe metal is forced, and means for cleaving the metal as it passes through said annular passage.

G. fr device for reducing` a metal billet to sheet form comprising: a cylinder having a die opening at one end, a piston arranged to operate .in said cylinder and to force the metal contained in a billet placed in said cylinder through said die opening, a mandrel detachably mounted. at one end in the face of said piston and extending forwardly through passage provided for the purpose in the billet and through said die opening, said mandrel being smaller than said die opening to thereby form an annular passage through Which said metal is forced, means for cleaving the metal as it passes through said annular passage, and means for spreading out the split tube into a flat sheet form.

7. A device for reducing a metal billet to she-et form comprising: a cylinder having a die opening at one end, a piston arranged to operate in said cylinder and to force the metal contained in a billet placed in said cylinder through said die opening, a mandrel detachably mounted at one end in the face of said piston and extending forwardly through a passage provided for the purpose in the billet and through said die opening, said mandrel being` smaller than said die opening to thereby form an annular passage through which said metal is forced, means for scoring the annular body of metal as it passes through said opening, means for er;- `panding the tube to cause it to cleave along the scored line, and means for flattening out the split tube into fiat sheet form.

8. A device for reducing a metal billet to sheet form comprising: a cylinder having` a die opening at one end, a piston arranged to operate in said cylinder and to force the metal contained in a billet placed in said cylinder through said die opening, a mandrel detachably mounted at one end in the face of said piston and extending forwardly through a passage provided for the purpose in the billet and through said die opening, said mandrel being smaller than said die opening to thereby form an annular passage through which said metal is forced, means Y on the mandrel for scoring the body of metal. passing through said opening, means mounted on the outer end of the mandrel for expanding the scored tube and causing it to break along the scored line, and means for rolling the split tube into flat sheet form.

9. A device for reducing a metal billet to sheet forni comprising: a cylinder having a die opening at one end, a piston arranged to operate in said cylinder and to force the metal contained in a billet placed in said cylinder through said die opening, a mandrel detachably mounted at one end in. the face of said piston and extending forwardly through a passage provided for .the piupose in the billet and through said die opening, said mandrel being smaller than said die opening to thereby form an annular' passage through which said metal is forced, scoring means on the mandrel for scoring the body of metal passing through said opening, an inwardly-converging spreading member mounted on the outer end of the mandrel for expanding the scored tube and causing it to break along the scored line, and means for flattening out the split tube into Hat sheet form.

ALBERT F. ROCKWELL. 

